A boardview (component placement) file. Shared as “RT10M(DDR3)_MP(A02)_20090914_gerber.F2B” — a .f2b file, 2.09 MB.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @ShareMan_Electronic_Files. Enginerys does not host this file.
How to open a .f2b file
Boardview exported from Unisoft ProntoPLACE, occasionally used for MSI and industrial boards.
OpenBoardViewUnisoft ProntoPLACE viewer